1. Field of Invention
This invention relates to fluorinated .alpha.-carboxylic-.omega.-carbonyl fluorides and their preparation.
2. Prior Art
Fluoromonomers containing carboxyl or carboxylic ester groups, such as described in U.S. Pat. No. 3,546,186, issued Dec. 8, 1970, have been difficult to prepare. Such monomers are useful in preparing fluorohomopolymers or copolymers with tetrafluoroethylene. Thus, it would be advantageous to be able to prepare fluoromonomers easily.
Symmetrical difluoromalonic compounds of the formula CF.sub.2 Q.sub.2 where Q may be COOH, COOalkyl or COF are known (E. J. P. Fear et al., J. Appl. Chem., 5, 589-594 (1955); and J. Heicklen, J. Phys. Chem., 70, 618-627 (1966)). Ryazanova et al., Zh. Vses. Khim. Obshchest, 1972, 17, No. 3, 347-8, describe compounds of the formula ROOC(CF.sub.2).sub.n COF where n is 3, 4 or 6.